How to Set Idle

LSU-Mike

Member
Joined
Jun 10, 2019
Threads
15
Messages
46
I have a Kawasaki FH580V on my Scag Freedom Z. Recently replaced the governor shaft seal along with several other items (nothing with the carb). Starts up and seems to run fine while cool. After mowing a while the engine speeds up "considerably" when I disengage the blades. Even when the throttle is moved all the way to the slowest position the engine is well above a low idle. Although I tried to carefully get all of the springs and rods associated with the control panel (below the carb) properly reattached, I must have something out of position. I was careful to mark the governor shaft to realign it with the governor arm. Would misalignment here cause my issue, or is it possibly something else?

I have a copy of the Kawasaki service, but when reading how to set low and high idle speeds, I don't know what is meant by high idle position of the throttle. The specifications state "1 550" for low and "3 600" for high. Should there be a comma in the blank space of the values? I assume the low idle position is with the throttle pulled all the way back to "Slow." The only thing I have that can measure RPM is a strobe light app on my iPhone. Can I use that to measure the RPM on the screen at the top of the engine?
Thanks
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
59
Messages
15,305
The service manual does a good job of explaining how to assemble and adjust the governor. Your question about rpm’s has to do with idle speed only, which should be set between 550-600 RPMs. I suspect you have not set the static governor speed correctly. Reread the section (3) on how to do this. Finally I’ve never seen a phone tachometer application which will accurately read RPMs.
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
59
Messages
15,305
I just took a look at three other Kawasaki manuals and I think the speeds posted in the 580 manual is a misprint. Should be 1550 RPMs for idle speed and 3600 RPMs for high no load speed. Someone put a space in the wrong place.
 

LSU-Mike

Member
Joined
Jun 10, 2019
Threads
15
Messages
46
Thanks for the replies folks.
Rivets, I’ll look for section 3 and read it closely. If phone apps are inadequate, can you recommend something else. Affordability is a requirement because this will likely be one of those tools used only one time.
 

Tiger Small Engine

Lawn Addict
Joined
Dec 7, 2022
Threads
2
Messages
1,103
I have a Kawasaki FH580V on my Scag Freedom Z. Recently replaced the governor shaft seal along with several other items (nothing with the carb). Starts up and seems to run fine while cool. After mowing a while the engine speeds up "considerably" when I disengage the blades. Even when the throttle is moved all the way to the slowest position the engine is well above a low idle. Although I tried to carefully get all of the springs and rods associated with the control panel (below the carb) properly reattached, I must have something out of position. I was careful to mark the governor shaft to realign it with the governor arm. Would misalignment here cause my issue, or is it possibly something else?

I have a copy of the Kawasaki service, but when reading how to set low and high idle speeds, I don't know what is meant by high idle position of the throttle. The specifications state "1 550" for low and "3 600" for high. Should there be a comma in the blank space of the values? I assume the low idle position is with the throttle pulled all the way back to "Slow." The only thing I have that can measure RPM is a strobe light app on my iPhone. Can I use that to measure the RPM on the screen at the top of the engine?
Thanks
You need an accurate tachometer to set and check RPMs. I use a digital tachometer and typically set low idle to 1850 RPM. 3600 RPM is maximum on a small engine and it doesn’t have to be that fast.
 

slomo

Lawn Pro
Joined
Jul 14, 2019
Threads
78
Messages
5,084
Just get some cheap flea-bay tach. You can listen to a proper running mower. Neighbor or youtubes. Match the revs up by sound.
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
59
Messages
15,305
If your ears can accurately tell RPS’s, you have better hearing and have worked on more engines than 99.9% of the mechanics on the earth. Buying cheap most often results in buying twice. Some auto parts store have a free loaner program.
 

Freddie21

Well-Known Member
Joined
May 1, 2021
Threads
20
Messages
268
Inexpensive tack. Just clip the lean on the spark plug wire.
 
Top